A conventional storage system provides a host computer with volumes as storage areas according to the RAID (Redundant Arrays of Inexpensive Disks) configuration, by using a plurality of hard disk drives. The conventional storage system has dual controllers, each of which is equipped with multiple processors. These processors control the operation of the system based on the stored control information, and this control information is stored in a shared memory so that it can be accessed by multiple processors.
If the control information is stored in the shared memory as described above, it is necessary to control access by utilizing several processors in stead of a single processor, therefore, time to access the share memory becomes longer than time to access a local memory, this creates a bottleneck in enhancing the throughput of host command processing. Therefore, the usual configuration is to copy and use the control information, which should be shared, to a local memory located near the processor for a conventional storage system (see Patent Literature 1).